The Nexus; a powerful, destructive energy-ribbon and inter-dimensional portal is discovered by the Federation for the first time with the crew of the Enterprise-B. It claims the lives of hundreds of El-Aurian refugees aboard the SS Lakul and SS Robert Fox which were both destroyed by the ribbon. (Star Trek Generations)

Doing his part to save the Enterprise-B from being destroyed by the Nexus on her maiden voyage, Captain James Tiberius Kirk, one of the most celebrated Starfleet officers in history, is believed to be killed. (Star Trek Generations)